Development of human granulocytic anaplasmosis infection despite prophylaxis with a one-time dose of oral doxycycline after recent tick exposure

In this brief report, we present a case of human granulocytic anaplasmosis (HGA) infection despite a 1-time 200-mg oral dose of doxycycline. Prophylaxis with a 1-time dose of doxycycline after recent tick exposure has been shown to be effective in reducing the rate of Lyme disease. However, there is no current evidence that evaluates the efficacy of this single dose as a method of prophylaxis against HGA. This case report suggests that it may be ineffective in preventing HGA after recent tick exposure.